The invention relates to the sector of the remote controlling devices for machines in general and it relates particularly to a remote controlling device particularly suitable for being applied to rotatory finishing machines which are used for the distribution of asphalt during the execution of roadxe2x80x94works. Remote controlling of moving means by ether connections realised by transmitter and receiver, belongs to the known technique.
The more used techniques relate to the use of telecontrols which use luminous waves in the infrared field or radio controls which use electromagnetic waves in the frequency field of dozens megahertz.
In both the cases the connection takes place with an optical displacement, that is in the conditions in which the receiver and the transmitter are visible without the interposition of obstacles.
In particular, the at sight contact between the receiver installed on the operative machine and the transmitter installed on the ground at the disposal of the operator, is requested in order that the operator could control that all the manoeuvres of the operative machine can take place with security conditions.
The distances which can be covered using infrared telecontrols are not so wide as those which could be covered using radio controls with electromagnetic waves. Besides, in case of the use of infrared rays the reception remarkably suffers the environmental conditions because their diffusion is greatly attenuated by the presence of steam or carbonic anhydride.
Therefore, the transmission of complex information by infrared rays is not very reliable, while instead the electromagnetic waves, which permit among other things to cover wider distances and are insensitive to the environmental conditions, are suitable for transferring information of the on/off type. Besides, the connection by electromagnetic waves could be rendered more reliable by modulation and coding techniques of the controls.
The technique of remote controlling operative machines results particularly useful if applied to vibratory finishing machines for the laying off of the asphalt during the execution of roadxe2x80x94works because the working conditions for the operators which use such machines are very unhealthy for the presence of tar vapours.
Therefore, for such machines the use of the technique of remote controlling is proposed as a very useful system in order to preserve the sanity of the operators. But it requests that the control should be realised in condition of optical displacement and therefore of maximum functioning security considering the particular kind of work that the vibratory finishing machines execute.
The present invention intends therefore to realise a remote controlling device very reliable, having as main purpose that of permitting a sure check of the machine, being different the environmental conditions in which it operates.
Another purpose that the invention intends to achieve is for the remote controlling device permits the guide of the machine only when it is with optical displacement for the operator.
The said purposes are achieved by the realisation of a remote controlling device of an operative machine, comprising said remote controlling device a transmitter arranged on the ground at the disposal of an operator and a receiver arranged inboard and supplied with at least an accomplishment circuit connected with the controls of the machine itself, and it is characterised in that said transmitter comprises a first transmitting section of luminous infrared waves and a second transmitting section of electromagnetic waves, which cooperate with said receiver which comprises a first receiving section of said luminous infrared waves and a second receiving section of said electromagnetic waves, presenting said receiver electronic means suitable for realising a permission signal in order to activate said accomplishment circuit only if said first receiving section receives said luminous infrared waves emitted by said first transmitting section.
According to a preferred embodiment the device of the invention comprises a first transmitting section of luminous infrared waves which keeps the contact with a corresponding first receiving section of the receiver arranged inboard and a second transmitting section of electromagnetic waves which keeps the contact with a corresponding second receiving section of the same receiver. The transmitter is therefore supplied with two separated sources of signal: the infrared source which keeps the contact with the receiver and the source of radio waves which transmits with suitable modulation, preferably of frequency, the codes relative to the different commands which the operator gives the machine.
The radio waves, for the facility with which they can be modulated, guarantee a right reception of the commands, protected from interferences and mistakes in any different environmental condition. The infrared control, vicexe2x80x94versa, carries out the function of enabling in the receiver the execution of the commands.